Organophilic bentonite bodied lubricant containing a nitroparaffin



May 6, 1958 c. A. STRATTON 2,833,720

, ORGANOPHILIC BENTONITE BODIED LUBRICANT CONTAINING A NITROPARAFFINFiled Sept. 2. 1954 N/ TQOBENZE/YE IV/ TROPROPAA E 2/V/ TPOPPOPA/VEMTAWME TIM/V! PER (EN T OISPERSANT INVENTOR; C A. Jtra ttan WM Arrow/Ela "obtain a gel or grease.

United States ORGANOPHILIC 'BENTONITE BODIED LUBRI- CANT CONTAINING ANITRQPARAFFIN Charles A. Stratton, Caney, Kans., assignor to PhillipsPetroleum Company, a corporation of Delaware Application September2,1954, SerialNo. 453,721 I 18 Claims. (Cl. 252-495) This inventionrelates to lubricants. In one of its more specific aspects, thisinvention relates to bodied lubricants. In another of its more specificaspects, this purpose are the metal salts of long carbon chain saturatedand unsaturated fatty acids as, for example, potassium oleate, magnesiumstearate, aluminum p'almitate, et'c.,

although salts of aromatic-acids, such as lead 'naph'then'ate,

are also useful. It is commonly observed that lubricants 2,833,720Patented May 6, 1958 "ice - lithium, and other bentonites, particularly'of'the Wyomin types; magnesium bentonite (sometimes called hectorite')and saponite; also nontronite and attapulgita particw larly that of theGeorgia-Florida type. These clays characterized by an unbalanced crystallattice, are believed to have negative charges which arenormallyneutralized by inorganic cations. As found in nature, therefore, theyexist as salts of the weak clay-aci d with bases, such as the alkalioralkaline-earth, metal hydroxides. Bentonites which are particularlyuseful are, the swelling bentonites of the Wyoming type and the swellingmagnesium bentonites of the hectorite'type.

An organophilic bentonite, commonly used in the manufacture of bodiedlubricants from mineral. lubrieating oils, is formed by replacing theexchangeable inorganic cations of the bentonite with organic cationsfrom salts of aliphatic, cyclic, aromatic and heterocyclic amines,primary, secondary and'tertiary amines and polyamines, and quaternaryammonium compounds, such as to achieve complete removal of non-clayimpurities which would impart an abrasive character to the finishedlubricant. The reactive exchangeable inorganic cation, such as sodium orpotassium, of the dispersed bentonite is "replaced by the addition ofthe salt referred to above and'the modified clay is then filtered,washed,'dried and "groundinto a fine powder. Increasing the chain lengthproperties of the modified bentonite.

of an alkyl ammonium cation used to replace the exchangeable inorganiccation increases the 'organophilic A more com- "plete disclosure of thepreparation of organophilicbem consisting of these soap-in-oildispersions have a rela tively high thermal coeflicient of viscosityandthat at temperatures often encountered in machinery undernormaloperating conditions these greases become fluid, resulting inloss of thelubricant and damage to the inachinery. This is to a considerable extenta function of the melting point of the soap. Thus, the magnesium, zinc,

or aluminum soaps would not be desirable for high temperatureapplications because of their low melting points.

bodying agents increase the low ternperature consistency to such adegree that starting of cold machinery is diffi l l I One more recentlydeveloped type of bodied lubricant ,is one formed by colloidallydispersing an organophilic clay, commonly called bentone, in an organiclubricating "liquid, such as a petroleum lubricating oil, asyntheticlubricating oil, such ,as a diester or heavier :polyester,

or a mixture of suchflubricating oils, in a manner to Theclays which areuseful as starting material for making the modified clay in acstantialbase-exchange properties, and particularly those exhibitingcomparatively high base-exchange properties and containing cationscapable of more orless easy retonite will be found in United StatesPatent 2,531,427,

issued to E. '-A. Hauser.

the invention'is to provide an improved lubricant bodied by an--org'anophilic clay. Another object of the invention is to provide .alubricant bodied by dispersing an organophilic clay in an organic.lubricating liquid with acetone and a nitroparaflin having from 1 to3;carbon ing of an organic lubricating liquid with an organophilicbentonite clay in the presence of a nitropara'flin having from 1 to 3carbon atoms per molecule. The use of such nitroparatnns as dispersionagents results in agrease which has good consistency. However, I havediscovered that over and beyond that improvement, the formation "of agel which has not only good consistency but also H V V -nitr'oethane,2-nitropropane and l-nitropropane. cordance with this invention arethose exhibiting subgood Work stability by dispersion of an organophilicbentonite in an organic lubricating liquid is aided by the addition of asmall amount of acetone together with a nitroparafiin selected from thegroup of nitromethane, The adaptability of the Z-nitropropane andl-nitropropane as a portion of the dispersion agent is dependent uponwhether or not the grease which is desired is a relatively soft grease.Furthermore, as will be disclosed hereinafter, a-greater amount ofeachof'the nitropropanes ,is necessary to;-obtain a minimum unworkedmicropenetration than; is necessary" when using nitromethane ornitroethane. v t Dispersion agents, such as ethyl acetate, acetic acid,acetone, methyl. alcohol, ethyl alcohol, ben zoyl chloride,

butyl ,stearate, coconut oil, cyclohexanone, ethylene dichloride,; ethylester, furfuraLisoamyl acetate, methyl ethyl ketone, and nitroberzene,,have been disclosed by the prior art as being 'solvat'ing agentswhich can be used in creating'an organophilic bentoniteclaythickenedgrease composition. I; have foundthat the ,,di spersion -of an organophilic bentonite in ,a lubricating liquidto form. a gelhaving'goodconsistency, and also good work stability can be facilitatedby the use of a combination of acetone and at least one of thenitroparatfins of the group of nitro- The prior art has not suggestedthe use of such materials as dispersing agents in; the formation of anorganophilic characteristics}; I have discovered that the suitability ofthe alkyl nitro -parafiins is inverseto the number of carbon; atoms in.the alkyl radical- 0f the two nitropropanes, 2-

persion agent than is l-nitropropane, either alone,,:in combinationwithanother,. nitroparafiin or in combination with acetone. I o l p 1 Betternnderstandingof this invention willbe obtained tionas contrasted withcertain dispersants fromthe prior I The amount of dispersing agent whichis utilized in 35 my grease dependentfupon not only theflspecifie dis-'persing agent, but is also dependent upon the concentration of theorganophilic bentonite clay, thetype of that clay, such as .Bentone18,..Bentone 34,,etc., andrthe the range :of from 2 to 35 percent,depending upon the apesnzo methane, nitroethane, Z-nitropropane andl-nitropr opane.

bentonite. clay thickened greaseicompositionnor has it suggested the useofcombinations of nitroparaffins and acetone to provide an organophilicbentonite clay thickenedgrease composition having improved workstability nitropropaneis much more adaptable for use as a disspecificlubricating liquid used. In general, the organo- 1 philic bentonite clayis used ina concentration within specific grade of grease desired. Theamountpf disperse ing agentwhich is usedyaries above 0.25, weightpercent,

generallywithintthe rangeof from 0.25 to 6 percent by weight, the.specific amount oncev again beingdependent upon the bentoniteconcentration, the-type of organow philic bentonite clay used and thelubricating liquid useds I havediscovered that the aIkyInitrOparatfinshaving from g l to 3 carbon atoms per molecule can be used in the aboveconcentrations If desired, they can be used in combination.Ihavefurtherdiscovered thatnitroparaffins having from 1 to 3 carbonatoms per molecule, and particu larly nitromethane or nitroethanqcan beutilized in admixture with acetone which is'a conventional dispersionagent for anorganophilic bentonite clay, so as to obtain o a greasewhich has a better consistency than 'does a grease, which is formedutilizing, acetone in an a sum equal :to the total amountof the mixturebf. acetone and ,nitroparaflina I have found that an. improvedorganophilic bentonite clay type grease can.beformed whenyusing at leastt) .25 percent byqweight total dispersants When ,a

mixture of, acetone and a- .nitroparafhn is. used. as the dispersant inamounts within the range set forth above,

the grease is improved when the nitroparalfin, preferably I nitromethaneor nitroethane,;is present in anfamount of at least 0.05 percent byweight.

q i The bodied lubricant. is formed from .an organic'lubricating liquid,such as. petroleum mineral oil, polyesters,

silicone oils, and .thelikqyvhen using one or more of these alkylnitroparaflins alone or in combination with acetone as a dispersionagent. Outstanding properties of bodied is. improved by the use atparafiins as a part of the dispersion agent.

at least one of the alkyl nitro- The preparation of a bodied lubricantfrom an organophilic bentonite clay in a lubricating liquid is a rathersimple operation which is accomplished by thoroughly mixing thelubricating liquid and the organophilic bentonite clay with a dispersionagent. In some instances, it is advantageous to heat the mixture or workthe mixturein a milling operation, However, such steps are not alwaysnecessary.

In the preparation of a grease of the instant invention, it is preferredto use a lubricating oil, such as a mineral lubricating oil, a polyesteroil, or a silicone fluid, which is oxidant resistant. The selection ofthe specific type of oil for use in this grease depends to a largeextent upon the temperatures at which it is to be used. Oils whichcontain aromatics, as shown by low viscosity indiccs, produce greaseswhich give higher consistencies at lower temperatures than do oils oflesser aromatic content with higher viscosity indices. When greases areto be used at high temperatures, however, high viscosity oils arepreferably utilized for the reason that less heat breakdown isencountered with the, use ofsuch oils. Polyester oils and siliconefluids are particularlyuseful in the production of greases to be used athigh temperatures, as such oils are particularly heat-resistant.

The dispersion of organophilic bentonite clay in the oil phase may beaccomplished rather easily while using a cold oil. The dispersion can bemade even more readily, however, by heating the oil to a temperaturebelow its decomposition point but preferably to a temperature butslightly above atmospheric temperature.

Minor proportions of conventional oxidation inhibitors, such asmercaptoaryl thiazoles, aminophenols, phenylene diamines, andphenyl-a-naphthyl amine, may be incorporated in the grease for thepurpose of improving the oxidation resistance of the oil base.

. The percentage of organophilic bentonite clay which may be 'used toproduce a satisfactorynlubricant of this invention usually lies in therange of 2 to 35 weight percent based on-the finished lubricant. Iprefer to use clay load- EXAMPLE I Bodied lubricants of similarcompositions were prepared from several different petroleum mineral oilstocks and including minor proportions of acetone or nitromethane. Givenquantities of commercial grade dimethyl dicetylammonium bentonite(Bentone 34), an organophilic bentonite clay available from the NationalLead Company, were mixed with small quantities of selected petroleummineral oil lubricating blending stock to form a slurry and minoramounts of acetone .or nitromethane were added to selected mixtures.Additional lubricating blending stock was then added at room temperatureto form a bodied lubricant. After thorough mixing,.the admixture wasmilled in a Navy grease worker using a worker plate containing 0.06 inchholes for 1000 strokes. The bodied lubricant was then de-aerated for tenminutes under a mechanical vacuum to remove the entrained air bubbles.These lubricants were then tested with a penetrometer, as described inASTM Test D-217-44T, but modified so as to use a micropenetrometerneedle, plunger and cup as described by Kaufman, Finn, and Harrington inIndustrial and Engineering Chemistry," Analytical Edition 11, 1081l0(1939). The lubricant composition and'micropenetrations are set forthbelow inTable I.

ama am Table I "Bentone 34" 7.0 7.0 20 Lubricating oil blending stock91. 5 91. 5 Nitrnm ath am: i 1. 5 Acetone 1'. 5

Micropenetration 105 S4 "Bentone 34"". 5.0 5.0 250 Lubricating Oilblending stock 93. 5 Nitromethane 1. 5 Acetone Mieropenetrationn'nfl 193183 Bentone 34" 7.0 7. 0 200 Lubricating oil blending stock 91. 5 91.5Nitrmnethane- 1. 5 Acetone 1. 5

Mlcropenetration 382 319 As shown by the penetration tests, the bodiedlubricants prepared with nitromethane as the dispersant, have greaterconsistency than the bodied lubricants of similar composition preparedwith acetone as the additive material. V

EXAMPLEII 5.25 grams of Bentone 34" were slurried into 25.0 grams of 20lubricating oil blending stock. 1.12 grams of ethyl acetate were added,and the mixture was stirred until a gel was obtained. The gel was weak,having a micropenetration, obtained as disclosed in Example I, of 356.The Bentone" content of this grease was higher than iscommercially'feasible, and when additional oil was added to the greaseto bring the Bentone content "down to a reasonable value, the gel brokeup completely.

EXAMPLE III Two greases were prepared by stirring Bentone 34 into a 20lubricating oil blending stock until a smooth Grease 1 Grease 2Micropenetration Therefore, as shown by these data, the grease preparedby using nitromethane as a dispersant had a better temperatureresistance than the one using acetone as the dispersant.

EXAMPLE 1v Several comparative greases were formed in the followingmanner. 5.2 grams of Bentone 34 was added 'to 92.5 grams of 20lubricating oil blending stock. The Bentone 34 was allowed to becomewetted by the on and settle therein. The mixture was thereafter stirredin a mixer for five minutes to efiect a uniform slurry. Nitromethane wasadded to the slurry and the slurry was thereafter mixed for a period offive minutes. Acetone was then added and the mixture was stirred forthirty minutes. The mixture was then milled in a Charlotted mill, modelND-l with a three horse-power motor and a T-grooved rotator and statorat 0.003 inch clearance and 257 ml./ min. T he same procedure wasutilized in forming greases using only nitromethane or acetone as thedispersion agent, except that the mixtures in those cases was stirredfor a total of thirty minutes to obtain thorough mixing. Work stabilityof the greases was determined and the results are set forth below inTable III.

-Bentoi ie'34" Acetone A. S. '1. M. Standard Penetrations:

Table III NLGI grade one grease has a 60 stroke penetration limit withinthe range of between 310 and 340. It will be noted that neither thegrease utilizing nitromethane alone or the grease utilizing acetonealone falls within the required limits of the grade one grease. I havedetermined that for a grade one grease, it is necessary to utilize from1.2 percent to 1.7 percent of acetone and from 0.8 percent to 0.3percent nitromethane, respectively, when a total of two percentdispersion agent is utilized in order to meet the requirements for NLGIgrade one grease. As the amount of nitromethane in the grease wasdecreased and the amount of acetone was increased, a softer grease wasobtained.

Table II Grease 1 Grease 2 6 20 Lubricating oil blending stock 732 G 732G. Bentone 34 66 56 Acetone 12 Nitromethane 12 Micropenetration 109 79 Asample of each of these bodied lubricants was heated on a hot plate in a50 milliliter beaker. The two samples were heated side by side on thesame hot plate and the temperature of each was determined by means of ather- Although the above examples have been specifically drawn to theuse of nitromethane and acetone as dispersion agents, additional datahave been obtained showing the comparative usefulness of nitroethane,2-nitropropane, and lanitropropane, in comparison with two additionaldispersing agents of the prior art. Those two additional prior artdispersing agents are methyl cellosolve and nitrobenzene. As will beapparent from the attached drawing, greater amounts of the nitropropancsare requiredto disperse 7 ,weight1percent Bentone 34 in20 lubricatingoil blending stock.

Various modifications of this invention will be apparend to thoseskilled in the art. Such modifications are believed tube within thespirit and the scope ofthis invention asset forth in this disclosure.

Iclaim: 1 t I 1. A bodied lubricant comprising an organic lubricatingliquid; a sufiicient amount of an organophilic ,bentonite clay tothicken said lubricating liquid to a grease consistency; and an amountof a mono-nitroparafiin containing from 1 to 3 carbon atoms per moleculesufficient to disperse said clay.

2. The lubricant of claim 1 wherein said nitroparafiin is nitromethane.

3. The lubricant of claim 1 wherein said nitroparatlin is nitroethane.

4. The lubricant of claim 1 wherein said nitroparaffin is2-nitropropane.

5. The lubricantof claim 1 wherein said nitroparaflin is l-nitropropane.

6. A bodied lubricant comprising between 65 and 97 weight percent of anorganic lubricating liquid; between 2 and 35 weight percent of anorganophilic bentonite clay, and between 0.25am! 6 weight percent of amono-nitroparaffin containing from 1 to 3 carbon atoms per molecule. g t

7. A bodied lubricant comprisingbetween 65 and 97 weightpercent of anorganic lubricating liquid; between 2 and 35 weight percent of anorganophilic bentonite clay, and between 0.25 and 6 weight percent of amixture of "acetone and a mono-nitroparafiincontaining from 1 to 3carbon atoms per molecule, wherein said nitroparafiin is present in saidmixture in an amount of at least 0.05 percent by weight. w

8. A lubricating composition having an organic lubricating liquid basebodied with an organophilic bentonite clay and containing as adispersant 0.25 to 6 weight percent of a mixture of acetone andnitromethane wherein said nitromethane is present in an amount of atleast 0.05 percent by weight.

9. A bodied lubricant comprising between 65 and 97 weight percentof anorganic lubricating liquid; between 2 and 35 weight percent of anorganophilic bentonite clay, and about 2 percent by weight of dispersantmaterial consisting essentially of nitromethane in the range of from 0.3to 0.8 percentand acetone in the range of from 1.2 to 1.7 percent byweight.

10. In producing a bodied lubricant by incorporating liquid, theimprovement which comprises using'as at least 8 a portion of thedispersant, a mono-ni-troparaflin contain ing from 1 to 3 carbon atomsper molecule.

I 11. A bodied lubricant comprising between and weight percent of anorganic lubricatingliquid; between 3 and 15 percent by weight of anorganophilic bentonite clay; and between 0.25 and 6 weight percent of amononitroparaflin containing from 1 to 3 carbon atoms per molecule.

12. A bodied lubricant obtained by dispersing between 2 and 35 weightpercent of an organophilic bentonite clay in from 65 to 97 percent byweight of an organic lubricating liquid in the presence of between 0.25and 6 weight percent of a mono-nitroparaffin containing from 1 to 3carbon atoms per molecule.

13. A bodied lubricant consisting essentially of an organic lubricatingliquid thickened to a grease consistency in the presence of a dispersingamount of a mononitroparafiin containing from 1 to 3 carbon atoms permolecule with between 2 and 35 percent by weight of a complex formed byreacting a bentonite clay with a salt of a material selected from thegroup consisting of amines and quaternary ammonium compounds.

14. The lubricant. of claim.13 wherein said organic lubricating liquidis thickened in the presence of nitromethane. t

15. The lubricant of claim 13 wherein said organic lubricating liquid isthickened in the presence of nitroethane.

16. The lubricant of claim 13 wherein said organic lubricating liquid isnitropropane.

17. The lubricant of claim 13 wherein said organic lubricating liquid isthickened in the presenceof 1- nitropropane.

18. A bodied lubricant comprising between 65 and 95 weight percent of anorganic lubricating liquid; and between 5 and 35 weight percent of anorganophilic bentonite, thickened to grease consistency in the presenceof between 0.4 and.5 weight percent of nitromethane.

References Cited in the file of this patent UNITED STATES PATENTS2,662,056 McCarthy Dec. 8, 1953 2,662,057 McCarthy Dec. 8, 19532,662,058 McCarthy Dec. 8, 1953 2,677,661 OH-alloran May 4, 1954 OTHERREFERENCES organophilic Bentonites--Swelling in Organic Liquids byJohnJordan, Journal of Physical and Colloid Chem.,.pages 294, 305, vol.53, No. 2, February 1949.

thickened in the presence of 2-.

1. A BODIED LUBRICANT COMPRISING AN ORGANIC LUBRICATING LIQUID; ASUFFICIENT AMOUNT OF AN ORGANOPHILIC BENTONITE CLAY TO THICKEN SAIDLUBRICATING LIQUID TO A GREASE CONSISTENCY; AND AN AMOUNT OF AMONO-NITROPARAFFIN CONTAINING FROM 1 TO 3 CARBON ATOMS PER MOLECULESUFFICIENT TO DISPERSE SAID CLAY.